drivers/comedi/drivers/das1800.c:343:2: warning: performing pointer arithmetic on a null pointer has undefined behavior

From: kernel test robot
Date: Sat May 27 2023 - 19:39:09 EST


Hi Yimin,

FYI, the error/warning was bisected to this commit, please ignore it if it's irrelevant.

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 4e893b5aa4ac2c8a56a40d18fe87e9d2295e5dcf
commit: b5e2c507b06c9d36411845149162a804ae7b04a9 riscv: Kconfig: Allow RV32 to build with no MMU
date: 9 weeks ago
config: riscv-randconfig-r042-20230528 (https://download.01.org/0day-ci/archive/20230528/202305280723.RB6YR0Ot-lkp@xxxxxxxxx/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project 4faf3aaf28226a4e950c103a14f6fc1d1fdabb1b)
reproduce (this is a W=1 build):
mkdir -p ~/bin
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install riscv cross compiling tool for clang build
# apt-get install binutils-riscv-linux-gnu
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b5e2c507b06c9d36411845149162a804ae7b04a9
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout b5e2c507b06c9d36411845149162a804ae7b04a9
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=riscv olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash drivers/comedi/drivers/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202305280723.RB6YR0Ot-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/riscv/include/asm/io.h:136:
include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writeb(value, PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:743:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
insb(addr, buffer, count);
^~~~~~~~~~~~~~~~~~~~~~~~~
arch/riscv/include/asm/io.h:104:53: note: expanded from macro 'insb'
#define insb(addr, buffer, count) __insb(PCI_IOBASE + (addr), buffer, count)
~~~~~~~~~~ ^
In file included from drivers/comedi/drivers/das1800.c:73:
In file included from include/linux/interrupt.h:11:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/riscv/include/asm/io.h:136:
include/asm-generic/io.h:751:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
insw(addr, buffer, count);
^~~~~~~~~~~~~~~~~~~~~~~~~
arch/riscv/include/asm/io.h:105:53: note: expanded from macro 'insw'
#define insw(addr, buffer, count) __insw(PCI_IOBASE + (addr), buffer, count)
~~~~~~~~~~ ^
In file included from drivers/comedi/drivers/das1800.c:73:
In file included from include/linux/interrupt.h:11:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/riscv/include/asm/io.h:136:
include/asm-generic/io.h:759:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
insl(addr, buffer, count);
^~~~~~~~~~~~~~~~~~~~~~~~~
arch/riscv/include/asm/io.h:106:53: note: expanded from macro 'insl'
#define insl(addr, buffer, count) __insl(PCI_IOBASE + (addr), buffer, count)
~~~~~~~~~~ ^
In file included from drivers/comedi/drivers/das1800.c:73:
In file included from include/linux/interrupt.h:11:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/riscv/include/asm/io.h:136:
include/asm-generic/io.h:768:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
outsb(addr, buffer, count);
^~~~~~~~~~~~~~~~~~~~~~~~~~
arch/riscv/include/asm/io.h:118:55: note: expanded from macro 'outsb'
#define outsb(addr, buffer, count) __outsb(PCI_IOBASE + (addr), buffer, count)
~~~~~~~~~~ ^
In file included from drivers/comedi/drivers/das1800.c:73:
In file included from include/linux/interrupt.h:11:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/riscv/include/asm/io.h:136:
include/asm-generic/io.h:777:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
outsw(addr, buffer, count);
^~~~~~~~~~~~~~~~~~~~~~~~~~
arch/riscv/include/asm/io.h:119:55: note: expanded from macro 'outsw'
#define outsw(addr, buffer, count) __outsw(PCI_IOBASE + (addr), buffer, count)
~~~~~~~~~~ ^
In file included from drivers/comedi/drivers/das1800.c:73:
In file included from include/linux/interrupt.h:11:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/riscv/include/asm/io.h:136:
include/asm-generic/io.h:786:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
outsl(addr, buffer, count);
^~~~~~~~~~~~~~~~~~~~~~~~~~
arch/riscv/include/asm/io.h:120:55: note: expanded from macro 'outsl'
#define outsl(addr, buffer, count) __outsl(PCI_IOBASE + (addr), buffer, count)
~~~~~~~~~~ ^
In file included from drivers/comedi/drivers/das1800.c:73:
In file included from include/linux/interrupt.h:11:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/riscv/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/riscv/include/asm/io.h:136:
include/asm-generic/io.h:1134:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
~~~~~~~~~~ ^
>> drivers/comedi/drivers/das1800.c:343:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
insw(dev->iobase + DAS1800_FIFO, devpriv->fifo_buf, nsamples);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/riscv/include/asm/io.h:105:53: note: expanded from macro 'insw'
#define insw(addr, buffer, count) __insw(PCI_IOBASE + (addr), buffer, count)
~~~~~~~~~~ ^
14 warnings generated.


vim +343 drivers/comedi/drivers/das1800.c

a69cc3a9fae82f drivers/staging/comedi/drivers/das1800.c Frank Mori Hess 2009-02-19 336
73e183c347242c drivers/staging/comedi/drivers/das1800.c H Hartley Sweeten 2012-05-23 337 static void das1800_handle_fifo_half_full(struct comedi_device *dev,
73e183c347242c drivers/staging/comedi/drivers/das1800.c H Hartley Sweeten 2012-05-23 338 struct comedi_subdevice *s)
73e183c347242c drivers/staging/comedi/drivers/das1800.c H Hartley Sweeten 2012-05-23 339 {
9a1a6cf8ae5ca5 drivers/staging/comedi/drivers/das1800.c H Hartley Sweeten 2012-10-15 340 struct das1800_private *devpriv = dev->private;
605d76f6eb007a drivers/staging/comedi/drivers/das1800.c H Hartley Sweeten 2014-11-05 341 unsigned int nsamples = comedi_nsamples_left(s, FIFO_SIZE / 2);
a69cc3a9fae82f drivers/staging/comedi/drivers/das1800.c Frank Mori Hess 2009-02-19 342
1f190a73590ce0 drivers/staging/comedi/drivers/das1800.c H Hartley Sweeten 2015-01-12 @343 insw(dev->iobase + DAS1800_FIFO, devpriv->fifo_buf, nsamples);
1f190a73590ce0 drivers/staging/comedi/drivers/das1800.c H Hartley Sweeten 2015-01-12 344 comedi_buf_write_samples(s, devpriv->fifo_buf, nsamples);
a69cc3a9fae82f drivers/staging/comedi/drivers/das1800.c Frank Mori Hess 2009-02-19 345 }
a69cc3a9fae82f drivers/staging/comedi/drivers/das1800.c Frank Mori Hess 2009-02-19 346

:::::: The code at line 343 was first introduced by commit
:::::: 1f190a73590ce0070d6a5b6ee0d50e076aafebd6 staging: comedi: das1800: separate AI FIFO bounce buffer from DMA buffer

:::::: TO: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
:::::: CC: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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